Surname Arethas (Арефа 
, Arethas 
) , across the world, is a rare family name. The cognomen Arethas is habitual in Greece, where it is a rare surname, Kyrgyzstan, where it is a very rare surname, and Ukraine. Measured by absolute frequency, it is the most numerous in Greece, the United States, and Ukraine. Very seldom, Arethas is the forename as well as the last name.